The C101 bypasses Duns to the south, but it isn't exactly a route that traffic will choose. It starts on the A6105 at Gavinton and runs east through the village, turning south east as it follows the Langton Burn round to meet the A6112. After a short multiplex eastwards, the C101 resumes, continuing east to a T junction. Here it turns left and then right at the next junction. At the end of this section of the road, it curves round to the left, passing under an old railway bridge to reach the A6105 once more at Crumstane.